Q: Sometimes I hear words that I don't understand. Where can I find out what different heating and air conditioning terms mean?

Q: What is the Green Sticker I have heard about, and why do I need one?

A: All appliances need to be checked and adjusted if necessary to meet changing natural gas supplies that will be introduced into the system in 2008. See the Green Sticker page of this site for more information.

Q: I need a heating/air conditioning contractor. How do I choose one?

A: Look for one who meets the following criteria.

Check credentials. Before making your selection, call the Better Business Bureau to make sure the dealer is reputable. Also, find out if the dealer is a member of a local or national association such as the Air Conditioning Contractors Association of America or the National Association for Technician Excellence (NATE).

Make sure the dealer is affiliated with a nationally known manufacturer. Dealers should be taking advantage of factory training offered by their manufacturer. As a result, when they make recommendations, you can be more assured that they've selected the right size system for your home, and that they've been trained in installation and service.

Ask for references. Former customers are an excellent source of information. Also, ask to see installation photos. A dealer that is proud of work will be more than happy to show it to you.

Ask around. You will always get a good recommendation when asking friends to refer you to someone. A friend will honestly tell you whether they have had a good or a bad experience with a company.

Expect an on-site evaluation of your home. A good dealer will take a thorough look at your home, ask questions and evaluate your overall comfort needs before making a recommendation. Beware of a dealer that simply takes information over the phone. A good dealer will also look the part. While he's evaluating your home, you should be evaluating him. Not only should he dress professionally, but his truck and printed materials should look professional as well.

Check local licenses. Depending on where you live, dealers may have to comply with certain local or state regulations, so ask to see proof of these licenses as well as insurance forms for liability and workmen's compensation.

Don't be afraid to ask questions. Ask for details about the firm's experience and the expertise of its staff. This is particularly important if you're also adding or changing ductwork ­ in this case, experience is definitely a factor in getting the job done correctly.

Get a written proposal. To make a fair comparison, make sure the proposals you receive are all based on the same efficiency and equipment. You'll also want to evaluate each dealer's personal business standards and policies. For example, will he remove old equipment? Will he relocate equipment if you want your new system installed in a different location? What are his clean up and care policies during installation? How will he handle emergency repair? These are just a few of the additional elements a good proposal will include.

Inquire about equipment and labor warranties. Limited warranties vary according to the manufacturer, so make sure you fully understand what you're getting. Also, don't forget to inquire about manufacturer's extended warranties at the time of purchase and other warranties provided by the dealer.

Ask about preventive maintenance service agreements. Many dealers offer service agreements that call for periodic maintenance of equipment, and if needed repairs. The fee for such agreements is usually well worth it in terms of obtaining optimum efficiency and performance for your system.

Insist on a written agreement. Commit your agreement to writing and have the dealer sign it.

Get specifics. Contractors should use the proper test and measurement equipment and tools like the HVAC calculator to determine the correct heating and cooling load requirements of your home.

Q: When should I replace my furnace?

A: It is recommend that a furnace be replaced when it is older than 12 years and if repair costs exceed 50% of the cost of a new system.